How to ... get 10% off everything

Discount codes can give you big savings on all kinds of stuff bought online, from computers to kids' toys - if you know where to find them. Hilary Osborne rounds up the best places to find the codes and the kind of discounts you can expect

At the checkout stage of a retail website, shoppers may be asked if they have a discount code (also known as a promotional code, rate code or gift certificate).

Once the code is entered - and, crucially, once it's validated - a reduction will be made in the price. Usually it's a fixed rate, such as 5% or 10% off the price of goods above a certain value. Some of the codes produce discounts on specific items, others offer free postage and packing.

Alternatively, head for moneysavingexpert.com and search for "discount codes" in the forums. Consumers who have been sent the codes often share them on this site, and users are also encouraged to post details of the codes they are looking for.

But probably the best approach is to shop for goods online in the normal way, then at the checkout stage, see if the retailer has a code box. If so, flip into Google and search for a code that might still be valid for that product.

Will the codes always work?

No. Finding codes that will work can be a time-consuming and frustrating business. They are always time limited, they can be withdrawn at any time - and many just don't work.

Hmmm ... So are they dodgy?

Some retailers are unwilling to honour codes that they did not intend for general use. Last October, Littlewoods withdrew a £25 discount after discovering that an offer designed for a small group of people had been picked up online and used by several thousand shoppers.

The retailer eventually backed down from its plans to reclaim the money from customers, but said Liverpool Trading Standards had supported its action. There is a chance other retailers will take a similarly hard line on offers that were designed with only a specific group of shoppers in mind.

Aren't these codes just a marketing gimmick?

They can be. Many of the "secret" codes are directly sent to websites by the retailers. Nick Beeny, who set up Sendmediscounts.co.uk five years ago and lists only codes sent by retailers, says stores are increasingly seeing discount codes as an extension of their marketing activity. So why not just discount everything? "They don't want to have a general sale for everyone," Beeny explains, "they want to keep the mystique of a secret sale."

Mark Pearson, whose site Myvouchercodes.co.uk lists codes sent by stores alongside those sent in by consumers, says it's a clever marketing method. "They send an offer to everyone on their email list and those people will do the work for them. They only need to send it once and it will spread like wildfire."

Not only does it cost less than traditional marketing, but this way of drumming up business has another advantage: some buyers still end up paying the full price for goods.

Some retailers post the codes on blogs and forums so they may look like they are being shared by consumers, when they have actually come from the shop itself. But does that matter if you are getting a discount on your shopping?

And the discounts can be substantial. This year, Pearson's site has listed codes offering £500 off a £2,000 plasma TV from Sharpe and money off a Sony Bravia TV at Tesco. So regardless of where the code comes from, the savings can be well worth having.

What's on offer at the moment?

Codes disappear rapidly, expecially if they have appeared in a newspaper. In May we went scouting around for codes, and found the following:

· Computer Dell's Inspiron 1720 with 320-gigabyte hard drive and all mod cons was selling for £649 on its website - £70 off its normal price. We almost doubled the saving by using a code (unfortunately it expired on May 14 - please note that all the codes mentioned here are likely to be out of date now).

· Outdoor living Are you after some garden furniture or plants to spruce up your outdoor space? We typed in 9133 at crocus.co.uk and found we could save 15% on everything.

· Children The code "mvcelc08" got us 10% off items at the Early Learning Centre (elc.co.uk) that were not already reduced.

· Clothing Planning to update your wardrobe? Asos (asos.com) offered £5 off purchases worth £60 and over with the rather more memorable "stylishsummer".

· Chocolate We got 10% off at Green & Blacks (greenandblacks.com) with "OUGB" - offsetting some of the £5 delivery cost for sending chocolates as a gift.

Note that some codes are sent to consumers to encourage them back to a service they have used in the past. For example, the DVD rental site Lovefilm (lovefilm.com) frequently sends codes to former customers offering its service free for up to three months. One recent code was "PRGLFRAF2".

It's the same story at Ocado, where customers who have used the food delivery service only sporadically are sent vouchers for items such as a free bottle of wine with their next order. So it's worth keeping an eye open - you could save a bundle.